(gud-display-line): Don't crash if BUFFER is nil.

1 files changed, 17 insertions, 15 deletions

diff --git a/lisp/gud.el b/lisp/gud.el
index cbbd4aeb2d9..281ceb50573 100644
--- a/lisp/gud.el
+++ b/lisp/gud.el
@@ -1355,22 +1355,24 @@ Obeying it means displaying in another window the specified file and line."
             (or (eq (current-buffer) gud-comint-buffer)
                 (set-buffer gud-comint-buffer))
             (gud-find-file true-file)))
-         (window (display-buffer buffer))
+         (window (and buffer (display-buffer buffer)))
          (pos))
-    (save-excursion
-      (set-buffer buffer)
-      (save-restriction
-        (widen)
-        (goto-line line)
-        (setq pos (point))
-        (setq overlay-arrow-string "=>")
-        (or overlay-arrow-position
-            (setq overlay-arrow-position (make-marker)))
-        (set-marker overlay-arrow-position (point) (current-buffer)))
-      (cond ((or (< pos (point-min)) (> pos (point-max)))
-             (widen)
-             (goto-char pos))))
-    (set-window-point window overlay-arrow-position)))
+    (if buffer
+        (progn
+          (save-excursion
+            (set-buffer buffer)
+            (save-restriction
+              (widen)
+              (goto-line line)
+              (setq pos (point))
+              (setq overlay-arrow-string "=>")
+              (or overlay-arrow-position
+                  (setq overlay-arrow-position (make-marker)))
+              (set-marker overlay-arrow-position (point) (current-buffer)))
+            (cond ((or (< pos (point-min)) (> pos (point-max)))
+                   (widen)
+                   (goto-char pos))))
+          (set-window-point window overlay-arrow-position)))))
 
 ;;; The gud-call function must do the right thing whether its invoking
 ;;; keystroke is from the GUD buffer itself (via major-mode binding)